Most commercially available feeders include what is referred to in the art as kicker feed--a pusher member which is reciprocated to engage the trailing end of the blank to be fed, push such blank to the nip rolls, decelerate and come to the end of its stroke and then to return to its initial position to engage the trailing end of the next blank. Kicker feed machines will often jam or misfeed if, among other reasons, a blank is warped or the edge of a blank is crushed or ragged. Such jams necessitate unloading the hopper which causes significant production delays. Moreover, the moving pusher bar, in close proximity to the operator's hands, can be a safety hazard.
One commercially available feeder which does not rely on kicker feed includes a reciprocated suction shuttle member. This machine is described in Bishop et al U.S. Pat. No. 3,105,681. This feeder requires nip rolls which are partially relieved to accommodate the forward position of the shuttle member. Such partially relieved rolls present a deflection problem especially on wide machines. These machines also involve use of a relatively high vacuum (e.g. 10 psi of vacuum), involving a relatively expensive vacuum pump instead of a simple blower. The reciprocation involved in the operation of the Bishop feeder has a tendency to move the blank to be fed away from the gates thereby causing it to be fed out of register.
Another commercially available feeder which does not rely on kicker feed includes partially relieved feed wheels which engage and grip a blank by means of static friction. This machine is described in Sardella U.S. Pat. No. 4,045,015.